Incandescent filament lamps

ABSTRACT

An incandescent filament lamp having an envelope closed with a wedge-shaped pinch seal and a cap disposed about the seal. The cap is closed by a plug of vitritelike material and an extension of said plug provides a seating structure for the seal.

Elaine Seams ateni Inventors John Willoughhy Thomas Wright, deceased late of Leicester, Engand by Audrey M. Wright and Denis W. Clarke, Leicester, England, legal executors; Trevor Humphery, London, England Appl. No. 829,157

Filed May 23, 1969 Patented Dec. 28, 1971 Assignee British Lighting Industries Limited London, England INCANDESCENT FILAMENT LAMPS 3 Claims, 2 Drawing Figs.

[15. Cl 339/145 R, 313/3 1 8 Int. Ci H01! 13/32 Field 0! Search 339/144,

[56] Reierences Cited UNITED STATES PATENTS 2,446,460 8/1948 Dillaby 339/145 2,483,351 9/1949 Richardson 339/99 2,749,527 6/1956 Gast 339/144 X 3,500,105 3/1970 Westlund,Jr. et a]. 313/318 FOREIGN PATENTS 559,836 7/1958 Great Britain 339/144 Primary Examiner-Richard E. Moore Attorney-Laurence Burns ABSTRACT: An incandescent filament lamp having an envelope closed with a wedge-shaped pinch seal and a cap disposed about the seal. The cap is closed by a plug of vitritelike material and an extension of said plug provides a seating structure for the seal.

PATENTED EH28 I971 JOHN WiL UGHBY THOMAS WRIGHT TREVOR PHERY INVENTORS BY W M woman INCANDESCENT FILAMENT LAMPS The present invention relates to the provision of cap connectors for the pinch sealed envelopes of lamps, such as, for example, fluorescent lamps, discharge lamps and incandescent filament lamps.

It has been proposed that lamp envelopes should be closed with a pinch seal through which terminal leads for connections to filaments or electrodes would be sealed. Such a pinch seal could be plugged directly into a socket thus dispensing with the need to seal a conductive cap onto the end of the envelopev However, the introduction of such a lamp would require replacement of all existing sockets by sockets adapted to receive pinch sealed lamps. This amount of obsolescence would not be acceptable in, for example, the field of domestic lighting, where it would involve the replacement of many millions of light fittings. It is however clear that considerable manufacturing advantages could be obtained if lamps were pinch sealed.

According to the present invention there is provided a lamp comprising an envelope having a pinch seal at one end thereof, at least one terminal wire sealed through and extending beyond said pinch seal, a cap disposed about said pinch seal having a base closed by a plug of vitritelike material, an extension of said plug of vitritelike material forming a seating structure for said seal, said terminal wire being connected at its outer end to said cap, whereby connection of said terminal wire to said cap holds said seal against said seating structure and prevents said envelope from moving axially relative to said cap.

ln a preferred form of the invention an incandescent filament lamp includes an envelope formed with a wedge-shaped pressed pinch seal, the thin end of the seal being the end remote from the filament, and a cap which is closed by a plug of vitritelike material, an extension of which forms seating structures which cooperate with the sides of the wedge-shaped seal to seat the envelope in the cap.

Advantageously, the pinch seal tapers on one or both sides from its center portion toward one or both of its edges.

The seating structures may include portions of a shape complementary to the shape of the seal whereby a face to face contact between the seal and the seating structure is maintained when the envelope is seated in the cap.

The invention will now be described, by way of example with reference to the accompanying drawings, in which:

FIG. 1 shows an exploded perspective view of an embodiment of the invention,

FIG. 2 shows a sectional view of the lamp shown in FIG. 1.

The lamp shown in the drawings comprises a glass envelope ll having a bulbous portion 12 which surrounds a filament l6.

Electrical connection to the filament 16 is made via two terminal wires 15 that are sealed through a wedge-shaped pinch seal 14. The thin end 25 of the seal is the end remote from the filament 16. The pinch seal 14 also tapers from its center portion 26 towards both of its edges 27. The glass envelope 1] is seated in a cap 17 and the terminal wires 15 pass through holes (not shown) in the base 18 of the cap 17 and are soldered or welded to the cap. A plug of vitrite 20 is secured in the cap 17 and is extended to provide a seating to locate and secure the wedge-shaped pinch seal in the cap. The vitrite forms a thick-walled hollow cylindrical member 28 adjacent the internal wall of the cap. Two cutout portions 29 and 31 are provided in the cylindrical member 28 and the faces of the cutout portions 29 and 31 engage against the flat sides 32 of the pinch seal to locate it in position. The cutout portions 29 and 31 taper in the direction of the base 18 of the cap 17 and also from their inner face in the direction of the face adjacent the interior wall of the cap 17. The shape of the cutout portions are thus complementary to the shape of the pinch seal enabling face-to-face contact to be maintained between them when the envelope 11 is seated in cap 17.

Although the cap shown in the drawings is a bayonet cap, it is clear that other types of caps, e.g. Edison screw caps or 2- pin caps, could be used.

We claim: I. An incandescent filament lamp comprising an envelope having a wedge-shaped pinch seal at one end thereof, the thin end of the wedge being along an edge at the end remote from the filament;

a pair of terminal wires sealed through said pinch seal in spacedapart relationship to one another and extending beyond said seal;

said terminal wires being connected at their inner ends to said filament;

a cap disposed about said seal having a base closed by a plug of vitritelike material;

an extension of said plug of vitritelike material forming seating structures disposed within said cap and abutting the sides of said seal,

said terminal wires being connected to said cap whereby said seal is held against said seating structures and said envelope is prevented from moving axially relative to said cap.

2. A lamp as claimed in claim 1, wherein said pinch seal tapers on at least one side from its center towards at least one edge.

3. A lamp as claimed in claim 1, wherein said seating structures has portions of a shape complementary to the shape of said seal whereby a face to face contact is maintained between said seal and said seating structure. 

1. An incandescent filament lamp comprising an envelope having a wedge-shaped pinch seal at one end thereof, the thin end of the wedge being along an edge at the end remote from the filament; a pair of terminal wires sealed through said pinch seal in spacedapart relationship to one another and extending beyond said seal; said terminal wires being connected at their inner ends to said filament; a cap disposed about said seal having a base closed by a plug of vitritelike material; an extension of said plug of vitritelike material forming seating structures disposed within said cap and abutting the sides of said seal, said terminal wires being connected to said cap whereby said seal is held against said seating structures and said envelope is prevented from moving axially relative to said cap.
 2. A lamp as claimed in claim 1, wherein said pinch seal tapers on at least one side from its center towards at least one edge.
 3. A lamp as claimed in claim 1, wherein said seating structures has portions of a shape complementary to the shape of said seal whereby a face to face contact is maintained between said seal and said seating structure. 